n = int(input())

dp = {}
dp[(1, 0)] = 0
dp[(1, 1)] = 1
dp[(1, 2)] = 0

for i in range(1, n+1):
	dp[(i+1, 0)] = dp[(i, 1)] + dp[(i, 2)]
	dp[(i+1, 1)] = dp[(i, 0)]
	dp[(i+1, 2)] = dp[(i, 1)]
	
print((dp[(n, 0)] + dp[(n, 1)] + dp[(n, 2)]) % 10**9+7)